As a means for observing portions that appear to be defects (hereinafter referred to as defect candidates) and are located at unspecified coordinate positions on a specimen (for example, on a semiconductor wafer) with the use of a charged particle beam, a charged particle beam apparatus (Defect Review SEM: DR-SEM) that automatically detects defects, observes the shapes of the defects, etc., and classifies the defects on the basis of an inspection result that is obtained in advance using an optical or electron beam defect inspection apparatus has been used. Defects are observed as follows with the use of the DR-SEM. First, a reference image that is used for being compared with a defect candidate and an image of the defect candidate are photographed at a low magnification. Both images will be referred to as a low magnification reference image and a low magnification defect image respectively hereinafter. With the use of the difference between both images, an accurate coordinate position of the defect candidate is specified. Subsequently, in order to easily judge whether the defect candidate is a true defect or not, the defect image is photographed at a high magnification (the defect image photographed at a high magnification will be referred to as a high magnification defect image hereinafter), and after a process that automatically detects a defect (Automatic Defect Review: ADR) is executed on the high magnification defect image, whether the defect candidate is a true defect or not is judged. In addition, with the use of a process that automatically classifies a defect (automatic defect classification: ADC), various classifications of shapes and the like are executed on the basis of the defect image.
In recent years, in association with the miniaturization and high integration of semiconductor manufacturing processes, the thicknesses of insulating films have been getting larger. Therefore, the depths of contact holes have been getting larger, the diameters of contact holes have been getting smaller, and the grooves of wiring patterns have been made deeper, with the result that the detection of defects relevant to a high aspect ratio (for example, a ratio between the depth and diameter of a contact hole) has been widely performed. However, ordinary electron beam scanning cannot uniformly charge a contact hole to its bottom, hence a potential contrast clear enough to detect a defect as a secondary electron image cannot be obtained. Therefore, it is necessary to irradiate an electron beam to form charge before photographing an image (irradiating an electron beam in advance will be referred to pre-charging hereinafter) to at least an area to be photographed on the surface of a specimen, that is, charge formation processing has to be executed in advance. For example, disclosed in Patent Literature 1 is a technology in which pre-charging is executed by scanning an electron beam to an area broader than an area to be photographed by switching from the magnification of photographing to a lower magnification. Hereinafter the area scanned with an electron beam in pre-charging will be referred to as a pre-charge scanning area.
The charge formation processing is used not only for defect detection but also for a charged particle beam apparatus (for example, Critical Dimension SEM: CD-SEM) in which the measurement of the shape, dimensions, etc. of a micropattern formed on a specimen are performed.
In the above mentioned charged particle beam apparatuses, because time required for the stage transfer occupies a large portion of time for inspecting one observation target, Patent Literature 2 proposes a technology in which time required for the stage transfer and the number of pieces of photographing can be reduced by grouping defect candidates within a certain distance so that these defect candidates are brought into one visual field and by inspecting these defect candidates afterward.